I am a 17-year-old female who has recently began experiencing some mild, but worrying cardiac symptoms. My heart is oversensitive to physical activity (not from being out of shape, as this started quite suddenly) and beats slightly faster than normal at rest. I get out of breath very easily and have palpitations when I lay down. Also, I sometimes get very dizzy. In other words, I just haven t been feeling right . After two months of these symptoms and a long-anticipated visit to the doctor, I had an ECG done and it came out completely normal, as did my blood tests. The doctor listened to my heart and said he heard nothing abnormal, except for a skipped beat when he had me perform the Valsalva maneuver which brought up the slight possibility of mitral valve prolapse. Although I was deemed completely healthy, I still want a second opinion and I want to know if it would be safe to go on roller coasters because I m going on a trip to Cedar Point soon. I know people with heart conditions should avoid rides.